Question about the disposition of their house

[Jubil]

English Grammar Tests, Elementary Level

ESL/EFL Test #35 "Question Tags (1)", question 9

They're selling their house .........

(a) will they?
(b) haven't they?
(c) aren't they?
(d) have they?

English Grammar Tests, Elementary Level

ESL/EFL Test #35 "Question Tags (1)", answer 9

They're selling their house aren't they?

Correct answer: (c) aren't they?
_________________________

I want to get an explanation of the test question.

Jubil

[Mister Micawber]

.
The exercise is to find the correct tag question. This question is asking about the disposition of their house.
.
_________________
Native English teacher at Mister Micawber's